The use of insect repellents is widely accepted throughout the world. Besides repellents intended for outdoor use, repellents are also available for use in homes to repel pests such as cockroaches, termites, ants, fleas, and so forth. The commercial standard for insect repellency is N,N-diethyl-3-methylbenzamide (DEET). The U.S. Environmental Protection Agency (EPA) estimates that more than 38% of the U.S. population uses a DEET-based insect repellent every year and that worldwide use exceeds 200,000,000 people annually (U.S. Environmental Protection Agency, PBS1-207722, 1980). However, DEET is known to cause severe adverse health effects in some people, particularly in higher concentrations. (See, for example, Qui et. al., 1998, J. Am. Mosq. Control Assoc. 14 (1):12-27; Miller, J. D., 1982, New Eng. J. Med. 307:1341-1342; Roland, et. al., 1985, Can. J. Med. Assn. J. 132:155-156).
Citronella is a biorational repellent that is also widely used. Although citronella poses less health risks than other, more toxic repellents, citronella is known to be highly volatile. As a result, any activity that might be present is lost rather quickly. In particular, citronella candles have been shown to be marginally effective, if at all.
Very little is known about the mechanisms involved in repelling many target pests such as cockroaches. It is also not known whether there are inherent differences between the ability of a male to detect a repellent as compared with a female of the same species.
What is needed, therefore, are new types of effective biorational repellents to replace commercial products that are toxic. The replacement repellents need to be economical, highly repellent to target pests, and pose less actual risk to the environment and humans as compared to traditional repellents.